Nonsterile Preparations - NAPLEX

SECTION 1

Historical Context & Motivation

Before the rise of large-scale pharmaceutical manufacturing, virtually every medication dispensed by a pharmacist was a compounded preparation. Apothecaries blended powders, mixed ointments, and formulated elixirs individually for each patient. The industrial revolution brought mass production, yet the need for individualized therapy never disappeared. Patients who cannot swallow tablets, who require dosage strengths unavailable commercially, or who are allergic to excipients in manufactured products still depend on nonsterile compounding to receive appropriate care. Understanding the historical evolution of compounding regulations helps pharmacists appreciate why current standards—particularly those set by the United States Pharmacopeia (USP)—exist and how they protect both practitioners and patients.

1820 • First USP Published

The first United States Pharmacopeia established national standards for drug identity, strength, and purity, laying groundwork for compounding quality expectations.

1938 • Federal Food, Drug, and Cosmetic Act

Following the sulfanilamide disaster that killed over 100 people, Congress mandated safety testing and formalized Good Manufacturing Practices, distinguishing manufacturing from pharmacy compounding.

2012 • NECC Meningitis Outbreak

Contaminated methylprednisolone injections from the New England Compounding Center caused a fungal meningitis outbreak, killing 76 patients and prompting sweeping regulatory reform.

2013 • Drug Quality and Security Act (DQSA)

Congress passed the DQSA, creating Section 503A for traditional compounding pharmacies and Section 503B for outsourcing facilities, clarifying FDA oversight authority.

2019–Present • USP ⟨795⟩ Revision

USP revised General Chapter ⟨795⟩ on nonsterile compounding, introducing beyond-use date categories, required quality controls, and formal training documentation for compounding personnel.

The central question driving modern nonsterile compounding is this: How can pharmacists prepare individualized, non-commercially-available dosage forms while ensuring they meet the same rigorous standards of identity, strength, quality, and purity that patients expect from manufactured products? The remaining sections of this lesson address that question through the lens of USP ⟨795⟩, pharmaceutical calculations, and practical compounding technique.

SECTION 2

Core Principles & Definitions

Nonsterile compounding encompasses the preparation of dosage forms that do not require sterility, including capsules, solutions, suspensions, ointments, creams, suppositories, and troches. The governing standard, USP General Chapter ⟨795⟩, applies to all healthcare settings—community pharmacies, hospitals, and physician offices—where personnel prepare nonsterile compounded preparations for human or animal use. Several foundational concepts underpin every aspect of this practice.

Master Formulation Record (MFR)

A detailed document containing the formula, equipment, procedures, quality checks, and beyond-use date (BUD) assignment for a specific preparation. It serves as the recipe that all compounding personnel follow.

Compounding Record (CR)

The batch-specific log documenting actual quantities measured, lot numbers of ingredients, date of preparation, assigned BUD, and the initials of the compounder and verifier. It provides full traceability.

Beyond-Use Date (BUD)

The date after which a compounded preparation should not be used. Unlike manufacturer expiration dates, BUDs are determined by the compounder based on USP guidelines, stability data, or the nature of the formulation.

Component Verification

Every active pharmaceutical ingredient (API) and excipient must be verified for identity, quality, and purity before use. Certificates of analysis (CoA) from suppliers and, where required, independent testing are essential.

Standard Operating Procedures (SOPs)

Written, facility-specific protocols covering equipment calibration, cleaning, personnel training, environmental controls, and quality assurance. SOPs ensure consistency and compliance across all compounding activities.

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KEY TAKEAWAY

Think of the Master Formulation Record as a chef's signature recipe—it specifies exact ingredients, proportions, techniques, and plating—while the Compounding Record is the kitchen ticket that tracks which chef prepared the dish, what lot of ingredients were used, and when it was served. Without both, you cannot guarantee that the patient receives a safe, reproducible product every time.

SECTION 3

Visual Explanation — Compounding Workflow

This flowchart illustrates the nine-step compounding workflow prescribed by USP ⟨795⟩. Documentation through the Compounding Record occurs at every stage to ensure full traceability from prescription receipt through dispensing.

The workflow depicted above emphasizes that nonsterile compounding is not a single act of mixing ingredients—it is a systematic process governed by documentation at every step. The Master Formulation Record (MFR) provides the standardized procedure for a given preparation, while the Compounding Record (CR) captures the unique details of each batch. Quality checks—visual inspection, weight verification, and organoleptic assessment—function as in-process controls. Only after a pharmacist performs final verification is the preparation deemed suitable for dispensing. This redundancy mirrors the check systems used in manufacturing and protects against compounding errors that could endanger patients.

SECTION 4

Pharmaceutical Calculations for Compounding

Accurate pharmaceutical calculations are the mathematical backbone of nonsterile compounding. Errors in arithmetic or unit conversion can lead to subtherapeutic or toxic preparations. The following equations represent the most commonly applied formulas in daily compounding practice.

PERCENTAGE STRENGTH (WEIGHT/VOLUME)

% w/v = (weight of solute in g ÷ volume of preparation in mL) × 100

Used for solids dissolved in liquid preparations. A 2% w/v solution contains 2 g of solute per 100 mL of final product.

ALLIGATION ALTERNATE

Parts of Higher = |Desired % − Lower %| Parts of Lower = |Higher % − Desired %|

Alligation alternate determines the ratio of two different concentrations of the same ingredient needed to produce a desired intermediate concentration. The absolute differences form a tic-tac-toe grid that yields the proportional parts.

DILUTION EQUATION

C₁ × V₁ = C₂ × V₂

C₁ = initial concentration, V₁ = initial volume, C₂ = final (desired) concentration, V₂ = final volume. This relationship holds for any dilution where the total amount of solute remains constant.

QUANTITY TO COMPOUND WITH EXCESS

Q_total = Q_prescribed × (1 + excess fraction)

When preparing capsules, ointments, or suspensions, compounders typically prepare an excess (often 10–20%) to account for material lost during trituration, transfer, and packaging. If a prescription calls for 30 capsules, compounding 33 (10% excess) ensures enough finished product.

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Double-Check Rule

USP ⟨795⟩ requires that all calculations be verified by a second qualified individual—typically the pharmacist—before compounding begins. This independent verification is analogous to the pilot-copilot cross-check in aviation and is one of the most effective error-prevention strategies in compounding practice.

SECTION 5

Dosage Form Classification & BUD Assignment

Nonsterile compounded preparations span a wide array of dosage forms, each with unique physical characteristics, stability considerations, and patient administration requirements. USP ⟨795⟩ categorizes compounded preparations by their beyond-use date (BUD) based on the type of formulation, availability of stability data, and whether aqueous ingredients are present. The revised USP ⟨795⟩ establishes default BUDs when preparation-specific stability data are not available, with the requirement that stability-indicating studies can extend these defaults.

Default BUDs under USP ⟨795⟩ are stratified by water content. Solid forms receive the longest default (180 days) due to low water activity, while aqueous forms are limited to 14 days without stability data because of heightened microbial growth risk.

Dosage Form	Route of Administration	Key Considerations	Default BUD
Capsules	Oral	Geometric dilution for potent APIs; weight variation ≤ ±10% of average	180 days
Oral suspensions	Oral	Uniform particle size; "Shake Well" auxiliary label; wetting agent may be needed	14 days (refrigerated)
Topical ointments	Topical	Levigation with ointment slab or electronic mortar; incorporate API uniformly	90 days
Suppositories	Rectal / Vaginal	Mold calibration required; displacement factor calculation essential	180 days (non-aqueous)
Troches / Lozenges	Oral (buccal dissolution)	Polyethylene glycol (PEG) or silicone molds; flavoring agents for palatability	180 days

Common nonsterile dosage forms with clinical and compounding considerations

SECTION 6

Worked Example — Compounding Progesterone Capsules

A prescriber writes an order for progesterone 200 mg capsules, #30, for a patient undergoing hormone replacement therapy. The pharmacy's Master Formulation Record specifies the use of micronized progesterone powder with Avicel PH-101 (microcrystalline cellulose) as the diluent. The MFR calls for a 10% excess to account for compounding losses. The target capsule shell size is #1, with a capacity of approximately 400 mg of powder.

Compounding 30 Progesterone 200 mg Capsules

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Step 1 — Calculate Total Capsules with Excess

The prescription calls for 30 capsules. With a 10% excess: Q_total = 30 × 1.10 = 33 capsules.

Prepare 33 capsules
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Step 2 — Calculate Total Progesterone Needed

Each capsule contains 200 mg of progesterone. For 33 capsules: 200 mg × 33 = 6,600 mg = 6.6 g of micronized progesterone.

6.6 g progesterone
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Step 3 — Calculate Total Capsule Fill Weight

Each #1 capsule holds approximately 400 mg. Total powder needed: 400 mg × 33 = 13,200 mg = 13.2 g.

13.2 g total fill
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Step 4 — Calculate Avicel Diluent Quantity

Avicel quantity = Total fill − Progesterone = 13.2 g − 6.6 g = 6.6 g of Avicel PH-101.

6.6 g Avicel PH-101
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Step 5 — Geometric Dilution & Encapsulation

Begin by placing 6.6 g of progesterone in a mortar. Add approximately an equal portion of Avicel (~6.6 g total, added in increasing portions: first ~6.6 g of Avicel divided into thirds). Triturate after each addition until homogeneous. Fill each capsule to a target weight of 400 mg using a capsule-filling device, then weigh 10 random capsules to verify ≤ ±10% weight variation from the average. Record all data on the Compounding Record.

Target: 400 mg per capsule (±40 mg)
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Step 6 — Assign BUD and Label

Since capsules are solid dosage forms and no stability-indicating data are available beyond the USP default, assign a BUD of 180 days from the date of compounding. Label with drug name, strength, quantity, BUD, storage conditions (room temperature or as specified), and the prescription number.

BUD: 180 days

SECTION 7

Quality Assurance, Strengths & Limitations

Nonsterile compounding occupies a unique niche in pharmacy practice, offering customization that commercial manufacturing cannot match, yet carrying inherent limitations related to scale, reproducibility, and regulatory oversight. A clear-eyed assessment of both the advantages and challenges helps compounding pharmacists maintain the highest standard of patient care.

Strengths	Limitations
Provides patient-specific dosing (pediatric, geriatric, veterinary) not available commercially	Shorter BUDs compared to commercially manufactured products
Allows removal of allergens, dyes, or preservatives problematic for individual patients	No FDA pre-market review; relies on compounder competency and state board oversight
Addresses drug shortages by compounding from bulk APIs when approved products are unavailable	Batch-to-batch variability is higher than industrial GMP manufacturing
Enables alternative dosage forms (liquid from tablet, topical from oral) for dysphagia or noncompliance	Limited analytical testing capability in most community pharmacy settings
Supports orphan disease populations and combination therapies	Potential for contamination if SOPs, training, or environmental controls are inadequate

Comparative assessment of nonsterile compounding strengths and limitations

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KEY TAKEAWAY

Nonsterile compounding is like custom tailoring in fashion—it delivers a perfectly fitted product for individual needs that off-the-rack (commercial) options cannot satisfy. However, just as a bespoke suit depends entirely on the skill and quality controls of the tailor, a compounded preparation is only as safe as the processes, training, and documentation behind it. The pharmacist must continuously balance the benefit of customization against the limitations of a small-scale production environment.

Quality Assurance Measures

✓ Weight variation testing: For capsules, weigh a minimum of 10% of the batch; individual weights should not deviate more than ±10% from the average capsule weight.
✓ Visual and organoleptic inspection: Assess color uniformity, absence of particulate matter, appropriate texture, and consistency with expected characteristics.
✓ pH testing: For aqueous preparations, verify pH falls within the acceptable range for stability and patient comfort.
✓ Equipment calibration: Balances must be calibrated and verified per facility SOP; Class III prescription balances have a minimum weighable quantity based on their sensitivity requirement.

SECTION 8

Regulatory Framework — USP ⟨795⟩ vs. ⟨797⟩ and 503A vs. 503B

Pharmacy compounding exists within a complex regulatory ecosystem that distinguishes between nonsterile and sterile preparations, as well as between traditional compounding pharmacies and outsourcing facilities. Understanding these distinctions is essential for NAPLEX preparation and daily pharmacy practice. The two most critical regulatory frameworks are the USP general chapters and the federal DQSA sections.

Feature	USP ⟨795⟩ — Nonsterile	USP ⟨797⟩ — Sterile
Scope	Oral, topical, rectal, vaginal, and other non-injectable routes	Injectables, ophthalmic, inhalation, and other forms requiring sterility
Environment	Dedicated compounding area; environmental controls not as stringent	ISO-classified cleanrooms, PECs (e.g., laminar airflow hoods), strict air quality monitoring
Garbing	Clean clothing, gloves, hair containment	Full gowning, sterile gloves, face masks, shoe covers, goggles
BUD Defaults	Up to 180 days (solids) / 14 days (aqueous) / 90 days (nonaqueous)	Ranges from 1 hour (immediate use) to 45 days based on risk category
Testing	Visual inspection, weight variation, pH as applicable	Sterility testing, endotoxin testing, media-fill testing, environmental monitoring

Comparison of USP ⟨795⟩ (nonsterile) and USP ⟨797⟩ (sterile) compounding standards

Section 503A vs. 503B of the DQSA

Under the Drug Quality and Security Act (DQSA) of 2013, Section 503A governs traditional compounding pharmacies that prepare medications pursuant to individual patient prescriptions under the supervision of a licensed pharmacist. These pharmacies are primarily regulated by state boards of pharmacy and must comply with USP ⟨795⟩ or ⟨797⟩. In contrast, Section 503B created a new category of "outsourcing facilities" that may compound without individual prescriptions and distribute to healthcare facilities, but must register with the FDA, comply with current Good Manufacturing Practices (cGMP), and submit to FDA inspections. This dual-track system arose directly from the NECC tragedy and represents Congress's effort to close the regulatory gap between traditional compounding and large-scale drug manufacturing.

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NAPLEX Alert

Expect NAPLEX questions distinguishing 503A and 503B entities. Key differentiators: 503A requires a patient-specific prescription, is state-regulated, and follows USP standards; 503B does not require a patient-specific prescription, must register with the FDA, and must follow cGMP. Both must use ingredients from FDA-registered sources.

SECTION 9

Practice Problems

Question 1: CONCEPTUAL

A pharmacy technician asks why a compounded oral suspension of metformin receives a beyond-use date of only 14 days, while a compounded capsule formulation of the same drug receives a BUD of 180 days. What is the pharmacist's best explanation based on USP ⟨795⟩?

Show answer

Under USP ⟨795⟩, BUD assignment is based on the physical characteristics of the dosage form, not the drug itself. Aqueous preparations (such as oral suspensions) default to a 14-day BUD when refrigerated because the presence of water promotes microbial growth and may accelerate chemical degradation. Solid dosage forms (capsules) have minimal water activity, making them inherently more stable, and thus receive a 180-day default BUD. If preparation-specific stability data were available, the BUD for the suspension could potentially be extended beyond the default. This distinction underscores the principle that formulation type drives stability expectations.

Question 2: BASIC CALCULATION

A prescription calls for 120 mL of a 2% w/v hydrocortisone suspension. How many grams of hydrocortisone powder are needed?

Show answer

A 2% w/v solution contains 2 g of solute per 100 mL of preparation. Using the proportion: (2 g / 100 mL) = (x g / 120 mL). Solving for x: x = (2 × 120) / 100 = 2.4 g. Therefore, 2.4 g of hydrocortisone powder is required to compound 120 mL of a 2% w/v suspension. In practice, the compounder would prepare a small excess (e.g., 130 mL total) to account for losses during preparation, which would require approximately 2.6 g of drug.

Question 3: INTERMEDIATE

A pharmacist needs to prepare 60 g of a 3% salicylic acid ointment. The pharmacy stocks a 10% salicylic acid ointment and plain white petrolatum (0% salicylic acid). Using alligation alternate, determine how many grams of each are needed.

Show answer

Using alligation alternate, place the higher concentration (10%) and lower concentration (0%) on the left, and the desired concentration (3%) in the center. Parts of 10% = |3 − 0| = 3 parts. Parts of 0% = |10 − 3| = 7 parts. Total parts = 3 + 7 = 10 parts. For 60 g total: 10% ointment = (3/10) × 60 g = 18 g; White petrolatum = (7/10) × 60 g = 42 g. The pharmacist should weigh 18 g of the 10% salicylic acid ointment and 42 g of white petrolatum, then combine by geometric incorporation on an ointment slab until homogeneous. This preparation, being a nonaqueous semisolid, would receive a default BUD of 90 days per USP ⟨795⟩.

Question 4: APPLIED

A pediatrician prescribes omeprazole 2 mg/mL oral suspension for a 6-month-old with GERD. The pharmacy has omeprazole 20 mg capsules and a commercially available oral vehicle (OraPlus:OraSweet 1:1). The prescription is for 100 mL. How many capsules must be opened, and what is the compounding procedure?

Show answer

The total amount of omeprazole needed is 2 mg/mL × 100 mL = 200 mg. Each capsule contains 20 mg, so 200 mg / 20 mg = 10 capsules are needed. In practice, the compounder should prepare at least 110 mL (10% excess), requiring 220 mg or 11 capsules. To compound: open 11 capsules and place the granules in a mortar. Add a small amount (~5 mL) of the vehicle and triturate to form a smooth paste, wetting the granules. Geometrically add portions of the 1:1 OraPlus:OraSweet vehicle while mixing until the final volume of approximately 110 mL is reached. Transfer to an amber bottle (omeprazole is light-sensitive), add a "Shake Well" and "Refrigerate" auxiliary label, and assign a BUD of 14 days per USP ⟨795⟩ default for aqueous preparations.

Question 5: CRITICAL THINKING

A compounding pharmacy receives a complaint that a batch of compounded gabapentin 100 mg capsules appears to have inconsistent potency—some patients report the medication feels weaker than usual. As the pharmacist-in-charge, describe the systematic investigation you would conduct, referencing USP ⟨795⟩ requirements, and identify the most likely root cause.

Show answer

The investigation should begin with a review of the Compounding Record for the batch in question, verifying that the correct quantities of gabapentin and diluent were weighed, that lot numbers correspond to verified CoA documents, and that the calculations were independently checked. Next, review the weight variation data: if individual capsule weights deviate significantly from the mean (beyond the ±10% threshold), this suggests inadequate mixing or inconsistent filling technique. The most likely root cause in a potency complaint involving capsules is failure to perform proper geometric dilution during trituration, leading to non-homogeneous distribution of the API within the powder blend—some capsules may contain significantly more or less drug than the target 100 mg. The investigation should also check whether the balance was calibrated within its certification period and whether the minimum weighable quantity was respected. All findings must be documented as part of the facility's corrective and preventive action (CAPA) process. If the complaint is substantiated, the remaining preparations from the batch should be recalled and patients notified. Retraining on geometric dilution technique should be documented per USP ⟨795⟩ personnel requirements.

SUMMARY

Lesson Summary

Summary

Nonsterile compounding is governed by USP General Chapter ⟨795⟩, which establishes standards for personnel training, facility requirements, component verification, Master Formulation Records, Compounding Records, and beyond-use date assignment. Default BUDs depend on dosage form: 180 days for solids, 14 days for aqueous preparations, and 90 days for nonaqueous semisolids, all of which may be extended with preparation-specific stability data.

Essential compounding calculations include percentage strength, alligation alternate, the dilution equation (C₁V₁ = C₂V₂), and excess quantity calculations. Regulatory oversight occurs under Section 503A for traditional pharmacies (state-regulated, patient-specific prescriptions) and Section 503B for outsourcing facilities (FDA-registered, cGMP-compliant). Quality assurance measures—including weight variation testing, visual inspection, and geometric dilution—are critical to ensuring every compounded preparation meets the standard of identity, strength, quality, and purity that patients deserve.